JPH09199114A - Nonaqueous electrolyte secondary cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary cell having a high capacity and excellent load characteristics by using low crystalline carbon as a negative electrode material. SOLUTION: This cell is constituted by winding a belt-shaped positive electrode 1 having a positive electrode active material layer using lithium-contained transition metal chalcogenite as an active material in both surfaces of a belt- shaped positive electrode collector and a belt-shaped negative electrode 2 having a negative electrode active material layer using a carbon material as an active material in both surfaces of a belt-shaped negative electrode collector, through a belt-shaped separator 3. In this case, the negative electrode active material layer contains low crystalline carbon with a 3.4Å or more mean interlayer distance d002 and a 100Å or less crystallite size Lc in a direction of an axis (c), thickness of one surface of this negative electrode active material layer is 0.04mm or less, and when assuming xmm for length in a major axis direction of the belt-shaped negative electrode material layer and ymm for diameter of a cylindrical cell, a relation where x/y<2> is 1.8 or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte secondary battery such as a lithium secondary battery composed of a strip positive electrode and a strip negative electrode, and more specifically to the above non-aqueous electrolyte having improved charge / discharge characteristics. The present invention relates to an electrolyte secondary battery.

[0002]

2. Description of the Related Art As a negative electrode material for a lithium secondary battery,
Carbon is generally used. Carbon has a layered structure, and its crystallinity is determined by the temperature at which the raw material is fired. It is known that the higher the crystallinity of the carbon, the higher the capacity.

The existing natural graphite having the highest crystallinity has an average interlayer distance d ₀₀₂ of 3.35 Å, a crystallite size Lc in the c-axis direction of 1,000 Å or more, and a theoretical capacity of 3
It shows 72 mAh / g (that is, C ₆ Li). However, due to active research and development in recent years, many low crystalline carbons having a capacity far exceeding the theoretical capacity of graphite as described above have appeared.

For example, in the case of a polyacene-based organic polymer semiconductor obtained by firing a phenol resin at about 700 ° C., 850 mAh / g (3rd unit) per carbon weight.
5th Battery Symposium Summary 2B15), 680 mAh / g for carbon made by firing an organic polymer compound such as polyparaphenylene at 500-1,500 ° C (Nikkei Sangyo Shimbun 1
It has been reported that a high capacity (May 2, 994) can be obtained.

Such low crystalline carbon has an average inter-layer distance d ₀₀₂ much larger than that of natural graphite,
It has many pores other than the layered structure, and it is considered that a large capacity can be obtained because a large amount of lithium can be doped therein.

[0006]

However, the low crystallinity car
Bonn has a very high capacity, so when you make a battery,
There is currently no positive electrode material to be combined with them that corresponds to the capacity per weight or volume of the low crystalline carbon. For example, a typical positive electrode material, lithium cobalt oxide (LiCoO ₂ ), has 130 mAh /
g, lithium nickel oxide (LiNiO ₂ ) 190
It is mAh / g.

Therefore, in order to make the positive electrode capacity and the negative electrode capacity equal, the positive electrode active material layer must be thickened or the negative electrode active material layer must be thinned. Further, the low crystalline carbon having an amorphous structure exhibits electrical isotropy,
The conductivity of the particles is lower than that of graphite, and the diffusion rate of lithium in the pores that are often present in low crystalline carbon is very slow compared to that between the layers, so low crystalline carbon is used as the negative electrode. When used for, the load characteristics of the battery are worse than when graphite is used.

In view of the above circumstances, the present invention provides a non-aqueous electrolyte secondary battery such as a lithium secondary battery using a low crystalline carbon as a negative electrode material, and the thickness and length of the negative electrode active material layer. The purpose of this is to obtain a non-aqueous electrolyte secondary battery having a high capacity and excellent load characteristics by regulating the above.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above object, and as a result, in a lithium secondary battery using a low crystalline carbon as a negative electrode material, By making the negative electrode active material layer a thin structure of a specific thickness or less, load characteristics are improved, and by making this negative electrode active material layer a wide area structure of a specific length or more, it is possible to achieve high capacity. As a result, I came to complete the present invention.

That is, according to the present invention, a strip-shaped positive electrode having a positive electrode active material layer using a lithium-containing transition metal chalcogenide as an active material on both sides of the strip-shaped positive electrode collector, and a carbon material is activated on both sides of the strip-shaped negative electrode collector. In a cylindrical non-aqueous electrolyte secondary battery formed by winding a strip negative electrode having a negative electrode active material layer used as a substance through a strip separator, the negative electrode active material layer has an average interlayer distance d. ₀₀₂ is 3.4 Å or more, and a low crystalline carbon having a crystallite size Lc in the c-axis direction of 100 Å or less is contained, and the thickness of one side of this negative electrode active material layer is 0.04 mm or less. And the length of the strip-shaped negative electrode active material layer in the major axis direction is x mm, and the diameter of the cylindrical battery is y.
The present invention relates to a cylindrical non-aqueous electrolyte secondary battery characterized in that x / y ² is 1.8 or more in mm.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as shown in FIG. 1, a spirally wound electrode body 4 is constructed by winding a strip positive electrode 1 and a strip negative electrode 2 through a strip separator 3 made of polyethylene or the like. Then, this is housed in a cylindrical battery can 5, a non-aqueous electrolyte is further added thereto, and the container is sealed by a conventional method to obtain a cylindrical non-aqueous electrolyte secondary battery.

As shown in FIG. 2, the strip-shaped positive electrode 1 has a structure in which positive electrode active material layers 11A and 11B using lithium-containing transition metal chalcogenide as an active material are provided on both surfaces of a strip-shaped positive electrode current collector 10 such as an aluminum foil. The layers 11A and 11B are usually prepared by applying a coating liquid containing the above active material, a binder and a conductive auxiliary agent to both surfaces of the above current collector 10, drying and then pressure molding. To be done.

Here, the lithium-containing transition metal chalcogenide, which is the positive electrode active material, is conventionally known as a compound such as a complex oxide of lithium and a transition metal such as cobalt or nickel, a complex sulfide, or a complex selenide. Can be used, and among these, compounds such as lithium cobalt oxide (LiCoO ₂ ) and lithium nickel oxide (LiNiO ₂ ) are particularly preferably used.

As shown in FIG. 3, the strip-shaped negative electrode 2 is composed of strip-shaped negative electrode current collectors 20 such as copper foil having negative electrode active material layers 21A and 21B using a carbon material as an active material on both sides. The negative electrode active material layers 21A and 21B of
A coating liquid containing an active material made of a carbon material and a binder is applied to both surfaces of the current collector 20 and dried, and then pressure-molded.

Here, the carbon material as the negative electrode active material has an average interlayer distance d ₀₀₂ of 3.4 Å or more, preferably 3.5 Å
Above (usually up to 4.0Å), the crystallite size Lc in the c-axis direction is 100 Å or less, preferably 50 Å or less (usually 4.
Low crystalline carbon up to 5Å) is used. This low crystalline carbon is obtained, for example, by crushing bulk carbon obtained by firing petroleum pitch, carbon microbeads extracted from it, phenol resin, etc. at a temperature of 500 ° C or higher. The average particle size is usually 0.5 to 30
Used as a μm powder material.

The negative electrode active material layers 21A and 21B using such a low crystalline carbon as the active material have a thickness t of one side of 0.
It is necessary to be 04 mm or less (usually up to 0.02 mm), and if it is thicker than this, the load characteristics of the battery deteriorate.
Further, while the thickness is set to such a value, the strip-shaped negative electrode active material layers 21A and 21B (that is, the strip-shaped negative electrode 2) in the major axis direction are obtained so that a high capacity based on the low crystalline carbon can be obtained. When the length is xmm and the diameter of the cylindrical battery is ymm, x / y ² must be 1.8 or more, preferably 1.9 or more (usually up to 5.0). If the length x is shorter than this, it is difficult to increase the capacity of the battery due to the decrease in the negative electrode area.

As the non-aqueous electrolytic solution, one prepared by dissolving an electrolyte in an organic solvent is used. Organic solvents include phosphorus-containing organic solvents such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, etc. High ester, 1,2-
Dimethoxyethane, dioxolane, tetrahydrofuran, 2-methyl-tetrahydrofuran, diethyl ether, acetonitrile and the like are used. Further, as the electrolyte, LiClO ₄ , LiPF ₆ , LiBF ₄ , Li
AsF ₆ , LiSbF ₆ , LiCF ₃ SO ₃ , LiCF
₃ CO ₂ , Li ₂ C ₂ F ₄ (SO ₃ ) ₂ , LiN (CF
₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiC _n F
_{2n + 1} SO ₃ (n ≧ 2) and the like are used alone or in combination of two or more.

[0018]

EXAMPLES Next, the present invention will be described more concretely with reference to examples. However, the present invention is not limited to these examples. In each example,
"Carbon," which is a low crystalline carbon used as the negative electrode active material
“Bon A to C” are obtained by the following method.

<Carbon A> Bulk carbon obtained by firing petroleum pitch at 850 ° C. is crushed to obtain an average particle size of 10 μm.
A powder consisting of low crystalline carbon, which is
Bon A. This carbon A has a d ₀₀₂ of 3.8Å,
Lc was 12Å.

<Carbon B> Bulk carbon obtained by firing carbon microbeads extracted from petroleum pitch at 700 ° C.
Carbon was crushed to obtain a powder of low crystalline carbon having an average particle size of 10 μm, which was designated as carbon B. This carbon B had a d ₀₀₂ of 3.61Å and an Lc of 16Å.

<Carbon C> phenol resin at 700 ° C.
The bulk carbon that was baked in
A powder of low crystalline carbon having a size of μm was obtained, which was designated as carbon C. This carbon C has a d ₀₀₂ of 4.1.
0Å, Lc was 10Å.

Example 1 A powder of carbon A was used as a negative electrode active material, and PVDF (polyvinylidene fluoride) was used as a binder for the powder to prepare a coating liquid, which was used as a copper foil having a thickness of 0.018 mm. After being coated on both sides of the above, dried and then calendar roll pressed, a strip negative electrode was produced. Further, a powder made of lithium nickel oxide (LiNiO ₂ ) was used as the positive electrode active material, PVDF was used as the binder, and carbon black was used as the conductive additive to prepare a coating solution, which had a thickness of 0.02 mm.
The aluminum foil was coated on both sides, dried and then calendar roll pressed to produce a strip-shaped positive electrode.

The strip-shaped negative electrode active material layer has a dimension of 57 m in the minor axis direction.
m, the major axis direction (x) was 1,000 mm, and the thickness (t) on one surface of the active material layer was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer is 57 mm in the short axis direction and 900 mm in the long axis direction.
The thickness of one side of this active material layer was 0.04 mm.
These strip-shaped positive and negative electrodes were wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm interposed therebetween to form a spiral electrode body.

This spirally wound electrode body was incorporated into a 18650 type cylindrical iron can [diameter (y) 18 mm, height 65 mm], and as a liquid electrolyte, dimethoxyethane and propylene carbonate were used.
A solution obtained by dissolving 1.0 mol / liter of LiPF ₆ in a mixed solvent having a volume ratio of 1: 1 with that of the solution was injected, and the solution was sealed according to a conventional method to prepare a lithium secondary battery. The x / y ² of this battery was 3.09.

Example 2 A powder of carbon B was used as the negative electrode active material, and a coating liquid was prepared using PVDF as this and a binder, and this was coated on both sides of a copper foil having a thickness of 0.018 mm. After drying, a calendar roll was pressed to produce a strip negative electrode.
Further, as a positive electrode active material, lithium nickel oxide (Li
NiO ₂ ) powder is used as a binder and PV
DF, using a carbon black as a conductive aid to prepare a coating solution, apply this to both sides of an aluminum foil with a thickness of 0.02 mm, dry, and then calender roll press,
A strip positive electrode was produced.

The strip-shaped negative electrode active material layer has a dimension of 57 m in the minor axis direction.
The length (m) was 800 mm in the major axis direction (x), and the thickness (t) on one surface of the active material layer was 0.04 mm. The dimension of the belt-shaped positive electrode active material layer was 57 mm in the minor axis direction and 720 mm in the major axis direction, and the thickness of one surface of the active material layer was 0.06 mm. These strip-shaped positive and negative electrodes were wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm interposed therebetween to form a spiral electrode body.

This spiral electrode body was incorporated into a 18650 type cylindrical iron can [diameter (y) 18 mm, height 65 mm], and dimethoxyethane and propylene carbon were used as electrolytes.
A solution obtained by dissolving 1.0 mol / liter of LiPF ₆ in a mixed solvent having a volume ratio of 1: 1 with that of the solution was injected, and the solution was sealed according to a conventional method to prepare a lithium secondary battery. The x / y ² of this battery was 2.47.

Example 3 A powder of carbon C was used as the negative electrode active material, and PVDF was used as a binder for the powder to prepare a coating solution, which was applied to both sides of a copper foil having a thickness of 0.018 mm. After drying, a calendar roll was pressed to produce a strip negative electrode.
Further, as a positive electrode active material, lithium nickel oxide (Li
NiO ₂ ) powder is used as a binder and PV
DF, using a carbon black as a conductive aid to prepare a coating solution, apply this to both sides of an aluminum foil with a thickness of 0.02 mm, dry, and then calender roll press,
A strip positive electrode was produced.

The strip-shaped negative electrode active material layer has a dimension of 57 m in the minor axis direction.
The length (m) was 620 mm in the major axis direction (x), and the thickness (t) on one surface of the active material layer was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 57 mm in the minor axis direction and 560 mm in the major axis direction, and the thickness of one surface of the active material layer was 0.09 mm. These strip-shaped positive and negative electrodes were wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm interposed therebetween to form a spiral electrode body.

This spiral electrode body was incorporated into a 18650 type cylindrical iron can [diameter (y) 18 mm, height 65 mm], and as a liquid electrolyte, dimethoxyethane and propylene carbonate were used.
A solution obtained by dissolving 1.0 mol / liter of LiPF ₆ in a mixed solvent having a volume ratio of 1: 1 with that of the solution was injected, and the solution was sealed according to a conventional method to prepare a lithium secondary battery. The x / y ² of this battery was 1.91.

Comparative Example 1 The longitudinal direction (x) of the strip-shaped negative electrode active material layer was 550 mm (x / y).
² is 1.71), the thickness (t) of one surface of the active material layer is 0.07 mm, the longitudinal direction of the strip-shaped positive electrode active material layer is 495 mm, and the thickness of one surface of the active material layer is 0. A lithium secondary battery was produced in the same manner as in Example 1 except that the thickness was 0.067 mm.

Comparative Example 2 500 mm (x / y) in the major axis direction (x) of the strip-shaped negative electrode active material layer.
² is 1.54), the thickness (t) of one side of the active material layer is 0.07 mm, the major axis direction of the strip-shaped positive electrode active material layer is 450 mm, and the thickness of one side of the active material layer is 0 mm. A lithium secondary battery was produced in the same manner as in Example 2 except that the thickness was set to 0.11 mm.

COMPARATIVE EXAMPLE 3 The strip-shaped negative electrode active material layer had a major axis direction (x) of 390 mm (x / y).
² is 1.20), the thickness (t) of one surface of the active material layer is 0.07 mm, the longitudinal direction of the strip-shaped positive electrode active material layer is 355 mm, and the thickness of one surface of the active material layer is 0. A lithium secondary battery was produced in the same manner as in Example 3 except that the size was 0.16 mm.

With respect to the lithium secondary batteries (18650 type) of Examples 1 to 3 and Comparative Examples 1 to 3 described above, discharge capacities (charging current: 1 C) at current densities of 1 C and 3 C,
The capacity retention ratio of the 3C capacity to the 1C capacity was examined. However, the charge / discharge voltage range was 4.2V to 1.0V.

The results are shown in Table 1 below. A commercially available 18650 that uses graphite for the negative electrode
Type lithium secondary battery is usually t = 0.07-0.13.
mm, x / y ² is 0.8 to 1.7, and 1C capacity is 1.00
0-1,300mAh, 3C capacity is 870-1,200
mAh.

[0036]

From the results shown in Table 1 above, in the lithium secondary batteries of Comparative Examples 1 to 3, the 1C capacity was 1,
The effect of using a low crystalline carbon having a high capacity of 260 to 1,530 mAh, which is 1.5 to 3 times as high as that of graphite per weight of carbon, is not recognized so much. Also, the 3C capacity is
At 830 to 1,010 mAh for carbons A to C, the retention rate of 3C capacity to 1C capacity is 66 to 70%, which is lower than 85% or more of graphite, and the load characteristics are very poor. .

On the other hand, in the lithium secondary batteries of Examples 1 to 3 of the present invention, the 1C capacity is 2,0 for carbons A to C.
Remarkably increased to 10 to 2,500 mAh, and 3C capacity is 1,830 to 2,205 mAh for carbons A to C.
The retention rate of the 3C capacity with respect to the 1C capacity was 88% or more, and the load characteristics were remarkably improved.

Example 4 The dimensions of the strip-shaped negative electrode active material layer were 42 mm in the short axis direction and 790 mm in the long axis direction (x), and the thickness (t) on one side of the active material layer.
Was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 42 mm in the short axis direction and 713 mm in the long axis direction. These strip-shaped positive and negative electrodes are wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body.
A lithium secondary battery was produced in the same manner as in Example 1 except that this was incorporated into a 16500 type cylindrical iron can [diameter (y) 16 mm, height 50 mm]. The x / y ² of this battery was 3.09.

Example 5 The dimension of the strip-shaped negative electrode active material layer was 42 mm in the minor axis direction and 650 mm in the major axis direction (x), and the thickness (t) on one side of this active material layer.
Was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 42 mm in the minor axis direction and 590 mm in the major axis direction. These strip-shaped positive and negative electrodes are wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body.
A lithium secondary battery was produced in the same manner as in Example 2 except that this was incorporated into a 16500 type cylindrical iron can [diameter (y) 16 mm, height 50 mm]. The x / y ² of this battery was 2.54.

Example 6 The dimension of the strip-shaped negative electrode active material layer was 42 mm in the short axis direction and 485 mm in the long axis direction (x), and the thickness (t) of one side of this active material layer.
Was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 42 mm in the minor axis direction and 435 mm in the major axis direction. These strip-shaped positive and negative electrodes are wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body.
A lithium secondary battery was produced in the same manner as in Example 3 except that this was incorporated into a 16500 type cylindrical iron can [diameter (y) 16 mm, height 50 mm]. The x / y ² of this battery was 1.89.

Comparative Example 4 The long axis direction (x) of the strip-shaped negative electrode active material layer was 440 mm (x / y).
² is 1.72), the thickness (t) of one side of the active material layer is 0.07 mm, the major axis direction of the strip-shaped positive electrode active material layer is 395 mm, and the thickness of one side of the active material layer is 0. A lithium secondary battery was produced in the same manner as in Example 4 except that the thickness was 0.067 mm.

Comparative Example 5 The longitudinal axis direction (x) of the strip-shaped negative electrode active material layer was 400 mm (x / y).
² is 1.56), the thickness (t) of one side of the active material layer is 0.07 mm, the longitudinal direction of the belt-shaped positive electrode active material layer is 360 mm, and the thickness of one side of the active material layer is 0. A lithium secondary battery was produced in the same manner as in Example 5 except that the thickness was set to 0.11 mm.

Comparative Example 6 The longitudinal direction (x) of the strip-shaped negative electrode active material layer was 310 mm (x / y).
² is 1.21), the thickness (t) of one surface of the active material layer is 0.07 mm, the longitudinal direction of the strip-shaped positive electrode active material layer is 280 mm, and the thickness of one surface of the active material layer is 0. A lithium secondary battery was made in the same manner as in Example 6 except that the thickness was set to 0.16 mm.

With respect to the lithium secondary batteries (16500 type) of Examples 4 to 6 and Comparative Examples 4 to 6, the discharge capacities (charging current: 1 C) at current densities of 1 C and 3 C were obtained in the same manner as described above. The capacity retention ratio of 3C capacity to 1C capacity was investigated. The results are as shown in Table 2 below.

[0046]

From the results of Table 2 above, also in the 16500 type lithium secondary battery, as in the case of the 18650 type lithium secondary battery in Table 1, Comparative Examples 4 to 6 which are outside the scope of the present invention. The batteries have low capacity and low capacity retention, whereas the batteries of Examples 4 to 6 having the specific negative electrode constitution of the present invention have high capacity and improved load characteristics. You can see that it is.

Example 7 The dimensions of the strip-shaped negative electrode active material layer were 54 mm in the short axis direction and 3,550 mm in the long axis direction (x), and the thickness (t) on one surface of the active material layer was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 54 mm in the minor axis direction and 3,200 mm in the major axis direction.
These strip-shaped positive and negative electrodes were wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body, which was an R20 cylindrical iron can [diameter (y) 3
A lithium secondary battery was produced in the same manner as in Example 1 except that the lithium secondary battery was assembled in a height of 4.2 mm and a height of 61.5 mm. The x / y ² of this battery was 3.07.

Example 8 The strip-shaped negative electrode active material layer had a dimension of 54 mm in the short axis direction and 2,900 mm in the long axis direction (x), and the thickness (t) of one surface of the active material layer was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 54 mm in the minor axis direction and 2,600 mm in the major axis direction.
These strip-shaped positive and negative electrodes were wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body, which was an R20 cylindrical iron can [diameter (y) 3
A lithium secondary battery was produced in the same manner as in Example 2 except that the lithium secondary battery was assembled in a height of 4.2 mm and a height of 61.5 mm. The x / y ² of this battery was 2.47.

Example 9 The strip negative electrode active material layer had a dimension of 54 mm in the minor axis direction and 2,250 mm in the major axis direction (x), and the thickness (t) of one surface of the active material layer was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 54 mm in the minor axis direction and 2,030 mm in the major axis direction.
These strip-shaped positive and negative electrodes were wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body, which was an R20 cylindrical iron can [diameter (y) 3
A lithium secondary battery was produced in the same manner as in Example 3 except that the lithium secondary battery was assembled in a height of 4.2 mm and a height of 61.5 mm. The x / y ² of this battery was 1.92.

Comparative Example 7 The long axis direction (x) of the strip-shaped negative electrode active material layer was 2,000 mm (x
/ Y ² is 1.71), and the thickness (t) of one side of the active material layer
Is 0.07 mm, the longitudinal direction of the strip-shaped positive electrode active material layer is 1,800 mm, and the thickness of one side of the active material layer is 0.06 mm.
A lithium secondary battery was produced in the same manner as in Example 7 except that the thickness was 7 mm.

Comparative Example 8 The longitudinal direction (x) of the strip-shaped negative electrode active material layer was 1,800 mm (x
/ Y ² is 1.54), the thickness of one side of the active material layer (t)
Is 0.07 mm, the major axis direction of the strip-shaped positive electrode active material layer is 1,630 mm, and the thickness of one side of the active material layer is 0.11.
A lithium secondary battery was produced in the same manner as in Example 8 except that the thickness was changed to mm.

Comparative Example 9 1,410 mm (x) in the major axis direction (x) of the strip-shaped negative electrode active material layer
/ Y ² is 1.21), the thickness (t) of one side of the active material layer
Is 0.07 mm, the major axis direction of the strip-shaped positive electrode active material layer is 1,270 mm, and the thickness of one side of the active material layer is 0.16 mm.
A lithium secondary battery was produced in the same manner as in Example 9 except that the thickness was changed to mm.

Regarding the lithium secondary batteries (R20 type) of Examples 7 to 9 and Comparative Examples 7 to 9 described above, discharge capacities (charging current: 1C) at current densities of 1C and 3C were obtained in the same manner as described above. The capacity retention ratio of 3C capacity to 1C capacity was investigated. The results are as shown in Table 3 below.

[0055]

From the results shown in Table 3 above, also in the R20 type lithium secondary battery, the 18650 type and Table 2 of Table 1 were obtained.
As in the case of the 16500 type lithium secondary battery of Comparative Example 7, the batteries of Comparative Examples 7 to 9, which are outside the scope of the present invention, have a low capacity and a low capacity retention, whereas the specific negative electrode of the present invention. It can be seen that the batteries of Examples 7 to 9 having the structure have high capacity and improved load characteristics.

Example 10 The strip-shaped negative electrode active material layer had dimensions of 43 mm in the minor axis direction and 650 mm in the major axis direction (x), and the thickness (t) of one surface of the active material layer.
Was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 43 mm in the minor axis direction and 585 mm in the major axis direction. These strip-shaped positive and negative electrodes are wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body.
Example 1 except that this was incorporated into an R6 type cylindrical iron can [diameter (y) 14.5 mm, height 50.5 mm].
A lithium secondary battery was produced in the same manner as in. The x / y ² of this battery was 3.09.

Example 11 The dimension of the strip-shaped negative electrode active material layer was 43 mm in the minor axis direction and 525 mm in the major axis direction (x), and the thickness (t) on one side of this active material layer.
Was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 43 mm in the minor axis direction and 470 mm in the major axis direction. These strip-shaped positive and negative electrodes are wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body.
Example 2 except that this was incorporated into an R6 type cylindrical iron can [diameter (y) 14.5 mm, height 50.5 mm].
A lithium secondary battery was produced in the same manner as in. The x / y ² of this battery was 2.50.

Example 12 The dimension of the strip-shaped negative electrode active material layer was 43 mm in the short axis direction and 410 mm in the long axis direction (x), and the thickness (t) of one side of this active material layer.
Was 0.04 mm. The dimension of the belt-shaped positive electrode active material layer was 43 mm in the minor axis direction and 370 mm in the major axis direction. These strip-shaped positive and negative electrodes are wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body.
Example 3 except that this was incorporated into an R6 type cylindrical iron can [diameter (y) 14.5 mm, height 50.5 mm].
A lithium secondary battery was produced in the same manner as in. The x / y ² of this battery was 1.95.

Comparative Example 10 The longitudinal direction (x) of the strip-shaped negative electrode active material layer was 360 mm (x / y).
² is 1.71), the thickness (t) of one surface of the active material layer is 0.07 mm, the longitudinal direction of the strip-shaped positive electrode active material layer is 325 mm, and the thickness of one surface of the active material layer is 0. A lithium secondary battery was produced in the same manner as in Example 10 except that the thickness was 0.067 mm.

Comparative Example 11 The long axis direction (x) of the strip-shaped negative electrode active material layer was 320 mm (x / y).
² is 1.52), the thickness (t) of one surface of the active material layer is 0.07 mm, the longitudinal direction of the strip-shaped positive electrode active material layer is 290 mm, and the thickness of one surface of the active material layer is 0. A lithium secondary battery was produced in the same manner as in Example 11 except that the thickness was set to 0.11 mm.

Comparative Example 12 The longitudinal direction (x) of the strip-shaped negative electrode active material layer was 255 mm (x / y).
² is 1.21), the thickness (t) of one side of the active material layer is 0.07 mm, the longitudinal direction of the strip-shaped positive electrode active material layer is 230 mm, and the thickness of one side of the active material layer is 0 mm. A lithium secondary battery was produced in the same manner as in Example 12 except that the thickness was set to 0.16 mm.

Examples 10 to 12 and Comparative Example 10 described above
For the lithium secondary batteries (R6 type) of Nos. 12 to 12, the discharge capacities (charging current: 1C) at current densities of 1C and 3C and the capacity retention ratio of the 3C capacity to the 1C capacity were examined in the same manner as above. . The results are as shown in Table 4 below.

[0064]

From the results of Table 4 above, also in the R6 type lithium secondary battery, the 18650 type of Table 1 and the 16 type of Table 2 were used.
Similar to the case of the 500-type and R20-type lithium secondary batteries of Table 3, the batteries of Comparative Examples 10 to 12, which are out of the scope of the present invention, have low capacity and low capacity retention ratio. Examples 10-12 with specific negative electrode configurations of the invention
It can be seen that the above battery has high capacity and improved load characteristics.

Example 13 The dimensions of the strip-shaped negative electrode active material layer were set to 37 mm in the short axis direction and 350 mm in the long axis direction (x), and the thickness (t) of one surface of the active material layer was set.
Was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 37 mm in the short axis direction and 315 mm in the long axis direction. These strip-shaped positive and negative electrodes are wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body.
A lithium secondary battery was produced in the same manner as in Example 1 except that this was incorporated into an R03 type cylindrical iron can [diameter (y) 10.5 mm, height 44.5 mm]. The x / y ² of this battery was 3.17.

Example 14 The dimension of the strip-shaped negative electrode active material layer was set to 37 mm in the short axis direction and 280 mm in the long axis direction (x), and the thickness (t) on one side of this active material layer.
Was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 37 mm in the minor axis direction and 255 mm in the major axis direction. These strip-shaped positive and negative electrodes are wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body.
A lithium secondary battery was produced in the same manner as in Example 2 except that this was incorporated into an R03 type cylindrical iron can [diameter (y) 10.5 mm, height 44.5 mm]. The x / y ² of this battery was 2.54.

Example 15 The dimension of the strip-shaped negative electrode active material layer was 37 mm in the minor axis direction and 210 mm in the major axis direction (x), and the thickness (t) of one side of this active material layer.
Was 0.04 mm. The dimension of the strip-shaped positive electrode active material layer was 37 mm in the minor axis direction and 190 mm in the major axis direction. These strip-shaped positive and negative electrodes are wound with a polyethylene strip-shaped separator having a thickness of 0.02 mm between them to form a spiral electrode body.
A lithium secondary battery was produced in the same manner as in Example 3 except that this was incorporated into an R03 type cylindrical iron can [diameter (y) 10.5 mm, height 44.5 mm]. The x / y ² of this battery was 1.90.

Comparative Example 13 The longitudinal direction (x) of the strip-shaped negative electrode active material layer was 190 mm (x / y).
² is 1.72), the thickness (t) of one surface of the active material layer is 0.07 mm, the major axis direction of the strip-shaped positive electrode active material layer is 170 mm, and the thickness of one surface of the active material layer is 0 mm. A lithium secondary battery was produced in the same manner as in Example 13 except that the thickness was 0.067 mm.

Comparative Example 14 The longitudinal direction (x) of the strip-shaped negative electrode active material layer was 170 mm (x / y).
² is 1.54), the thickness (t) of one side of the active material layer is 0.07 mm, the longitudinal direction of the strip-shaped positive electrode active material layer is 155 mm, and the thickness of one side of the active material layer is 0. A lithium secondary battery was produced in the same manner as in Example 14 except that the thickness was set to 0.11 mm.

Comparative Example 15 The longitudinal direction (x) of the strip-shaped negative electrode active material layer was 135 mm (x / y).
² is 1.22), the thickness (t) of one surface of the active material layer is 0.07 mm, the major axis direction of the strip-shaped positive electrode active material layer is 123 mm, and the thickness of one surface of the active material layer is 0. A lithium secondary battery was produced in the same manner as in Example 15 except that the thickness was set to 0.16 mm.

Examples 13 to 15 and Comparative Example 13 described above
With respect to the lithium secondary batteries (R03 type) of Nos. 15 to 15, the discharge capacities (charging current: 1C) at current densities of 1C and 3C and the capacity retention ratio of the 3C capacity to the 1C capacity were examined in the same manner as described above. . The results are as shown in Table 5 below.

[0073]

From the results of Table 5 above, also in the R03 type lithium secondary battery, 18650 type of Table 1 and 1 of Table 2
6500 type, R20 type of Table 3 and R6 type of lithium secondary batteries of Table 4, the batteries of Comparative Examples 13 to 15, which are outside the scope of the present invention, show low capacity and low capacity retention rate. On the contrary, it can be seen that the batteries of Examples 13 to 15 having the specific negative electrode constitution of the present invention have high capacity and improved load characteristics.

Examples 16 to 21 Carbons A to C were used as the negative electrode active material, and the dimensions of the strip-shaped negative electrode active material layer (minor axis direction and major axis direction (y)) and the thickness of one side were changed. Along with this, except that the dimensions of the strip-shaped positive electrode active material layer (short axis direction and long axis direction) were changed appropriately, 18650-type six types of lithium secondary batteries were produced in the same manner as in Examples 1 to 3. did. Table 6 shows the thickness (t) and x / y ² on one surface of the strip negative electrode active material layer.

Regarding the lithium secondary batteries (18650 type) of Examples 16 to 21 described above, 1C was prepared in the same manner as described above.
And discharge capacity at 3C current density (charging current: 1C)
And the capacity retention ratio of 3C capacity to 1C capacity were investigated. The results are as shown in Table 6 below.

[0077]

From the results shown in Table 6 above, the thickness (t) of the negative electrode active material layer was 0.03 mm (Examples 16 to 18) and 0.
The thickness (t) of the negative electrode active material layer was 0.04 mm (Examples 1 to 21) by setting the value of x / y ² within the range of the present invention. As in the case of the battery of Table 1 described in 3), it can be seen that a high capacity and improved load characteristics are obtained.

Example 22 The major axis direction (x) of the strip-shaped negative electrode active material layer was 1,020 mm, and the thickness (t) of one surface of this negative electrode active material layer was 0.04 mm,
Further, except that the long axis direction of the strip-shaped positive electrode active material layer is 920 mm and the thickness of one surface of this positive electrode active material layer is 0.035 mm,
A 18650 type lithium secondary battery was produced in the same manner as in Example 1. The x / y ² of this secondary battery was 3.16.

Example 23 The belt-shaped negative electrode active material layer had a major axis direction (x) of 1,075 mm, and the thickness (t) of one surface of the negative electrode active material layer was 0.04 mm,
Further, a 18650 type lithium secondary battery was produced in the same manner as in Example 1 except that the long axis direction of the strip-shaped positive electrode active material layer was 965 mm and the thickness of one surface of the positive electrode active material layer was 0.03 mm. did. The x / y ² of this secondary battery was 3.33.

In the lithium secondary batteries of Examples 22 and 23, the weight ratio of the negative electrode active material to the positive electrode active material was increased by decreasing the thickness of the positive electrode active material layer, that is, the positive electrode active material. By reducing the weight of the substance, the charge capacity of the battery can be controlled with the allowable charge capacity of the positive electrode. For these batteries, the discharge capacity at a current density of 1 C (charging current: 1 C) and the number of cycles when the discharge capacity reached 80% of the initial value were examined. These results were as shown in Table 7 below. In addition, in the same table, the results of examining the lithium secondary batteries of Example 1 and Comparative Example 1 in the same manner as above are also shown.

[0082]

From the results of Table 7 above, Examples 22 and 23
The lithium secondary battery of Comparative Example 1, which has a capacity slightly decreased as compared with the battery of Example 1 controlled by the negative electrode charge capacity, is recognized to have improved cycle characteristics and is outside the scope of the present invention. It can be seen that a battery having a high capacity and excellent cycle characteristics can be obtained as compared with the battery of No. It is thought that the improvement in cycle characteristics is due to the fact that charging is performed at a capacity somewhat lower than the negative electrode allowable capacity, and the burden on the carbon material is small.

[0084]

As described above, according to the present invention, a lithium crystal using a low crystalline carbon having an average interlayer distance d ₀₀₂ of 3.4 Å or more and a crystallite size Lc in the c-axis direction of 100 Å or less is used. In a non-aqueous electrolyte secondary battery such as a secondary battery, the thickness of one surface of the strip-shaped negative electrode active material layer is 0.04 mm or less, and the length of this layer in the major axis direction is x mm, which is the outer surface of the cylindrical battery.
When the diameter is ymm, x / y ² is set to be 1.8 or more, whereby a battery in which the high capacity of the low crystalline carbon can be fully utilized can be manufactured, and It is possible to improve the low load characteristic, which is a drawback.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an example of a non-aqueous electrolyte secondary battery of the present invention.

FIG. 2 is a cross-sectional view showing the structure of a strip positive electrode.

FIG. 3 is a cross-sectional view showing a structure of a strip negative electrode.

[Explanation of symbols]

 1 band-shaped positive electrode 10 band-shaped positive electrode current collector 11A, 11B positive electrode active material layer 2 band-shaped negative electrode 20 band-shaped negative electrode current collector 21A, 21B negative electrode active material layer 3 band-shaped separator 5 cylindrical battery can t negative electrode active material layer one side Thickness x length of the strip-shaped negative electrode active material layer in the major axis direction y diameter of the cylindrical battery

Claims (1)

[Claims] 1. A strip positive electrode having a positive electrode active material layer using a lithium-containing transition metal chalcogenide as an active material on both sides of the strip positive electrode collector, and a carbon material used as an active material on both sides of the strip negative electrode collector. In a cylindrical non-aqueous electrolyte secondary battery formed by winding a strip negative electrode having a negative electrode active material layer via a strip separator, the negative electrode active material layer has an average interlayer distance d ₀₀₂ of 3. It contains low crystalline carbon having a crystallite size Lc in the c-axis direction of 100 Å or less and a crystallite size Lc of 4 Å or more.
x / y, where the length of the strip-shaped negative electrode active material layer in the major axis direction is x mm and the diameter of the cylindrical battery is y mm.
^2. A cylindrical non-aqueous electrolyte secondary battery, wherein ² is 1.8 or more.